This invention relates to a system for automatically stopping and restarting the internal combustion engine of a vehicle to conserve fuel when the vehicle is forced to stop intermittently for short periods of time. It also relates to such a system that measures and displays the amount of fuel saved by the automatic stopping and restarting operation.
In the normal day-to-day operation of automotive vehicles, such vehicles must often stop and remain stationary while their engine remains running. To conserve fuel during such stops, various schemes have been proposed for causing the engine to cease operation and then be restarted under certain operating conditions. Apparatus for accomplishing such engine operations is described in U.S. Pat. Nos. 3,731,108 and 4,006,723. Both of these prior systems are relatively complicated and require a relatively high level of manual control. For example, the U.S. Pat. No. 4,006,723 (Startomatic) patent discloses an apparatus utilizing relatively complicated circuitry comprised of a series of interconnected relays, switches, sensors and other elements, yet, in its operations, it requires manual actuation of a switch means for stopping the engine. In the U.S. Pat. No. 3,731,108 the vehicle operator is required to actuate switches on both the accelerator and the clutch before restarting a vehicle engine that has been previously stopped. The present invention provides a solution to the aforesaid problems with an improved, more versatile, and thus more effective, automatic engine stopping and starting system.
Another important feature of the present invention is that it provides an engine stop-start system which also measures and displays the amount of the fuel actually saved during the time that the engine is shut down for intermittent stopping periods. Thus, a vehicle owner can quickly ascertain the fuel being saved during a particular trip or over a certain time period.
It is, therefore, a general object of the invention to provide an improved system for automatically stopping and restarting an engine to conserve fuel at times it would ordinarily be running at idle speed.
Another object of the invention is to provide an engine stop/start system that will automatically calculate and display the amount of fuel saved during shutdown periods.
Another object of the invention is to provide an automatic engine stop/start system that is relatively simple but efficient, accurate and reliable and yet easy to install on a wide variety of conventional vehicles.
A more specific object of the invention is to provide an engine stop-restart system that will operate automatically to stop the vehicle engine when the vehicle is not moving, when its brake is on and a predetermined amount of time has elapsed after these events, which will restart automatically with the vehicle in gear or in the automatic "drive" position, when the vehicle accelerator is activated to close an auto start system, and which will compute and display the actual amount of fuel saved during the shutdown period.